Novel 18-oxygenated steroids and process of preparation



United States Patent G ce NOVEL IS-OXYGENATED STEROIDS AND PROCESS OFPREPARATION Georges Muller, Nogent-sur-Marne, and Jacques Martel, Bondy,France, assignors to Les Laboratoires Francais de Chimiotherapie, Paris,France, a corporation of France No Drawing. Filed Jan. 4, 1961, Ser. No.80,558 Claims priority, application France Jan. 15, 1960 14 Claims. (Cl.260-23955) This invention relates to new 18-oxygenated steroids and,more particularly, to compounds of the following general formula:

signed United States application, Serial No. 38,722, filed June 27,1960.

Applicants have discovered that it is possible to prepare 18,20 oxidosteroids having a 16-rnethyl by treatment with lead tetraacetate in thepresence of light without formation of 16,20 oXido steroids which resultWas not to be anticipated.

It is an object of the invention to obtain the 18-11 lactone of 3 11,11B,20;8-trihydroxyl 6a-methyl-55-pregnane-ISB-oic acid and the3,20-diacyloxy derivatives thereof which are novel intermediates for thepreparation of 16m-methyl aldosterone, which has enhanced aldosteronicactivity.

It is a further object of the invention to provide a process forpreparing the 18-11 lactone of 3a,1lfl,20,8trihydroxy-IGa-methyI-Sfi-pregnane-I8-oic acid and the 3,2G-diacyloxyderivatives thereof.

It is another object of the invention to obtain the following novelintermediates for the preparation of the 18-11 lactone of30:,115,20fl-trihydroxy-l6u-methyl-5fipregnane-lS-oic acid and the3,20-diacyloxy derivatives thereof.

a. The 3a-acetoxy-11-oxo-20a-hydroxy-16a-methyl-5flpregnane (Illa),

b. The 3a-acetoxy-l1-oxo-20B hydroXy-16a-methyl-SB- pregnane (IIIb),

c. The 3a-acetoXy-1l-oxo-l8,20a-oxido-16a-methyl-5B- pregnane (IVa),

d. The Su-acetOXy-Il-oxo-l8,20/3-oxido-16a-methyl-5flpregnane (IVb),

e. The 30:,20 dihydroxy 11,18 dioxo 18,20 oxido- 16a-methyl-5 8-pregnane(V).

2,984,662 Patented May 16, 1961 TABLE I if/W cu? L) orjcou@' CHa IIIbIVa

R represents hydrogen or the acyl radical of an ogranic carboxylic acidhaving from 1 to 18 carbon atoms.

The reduction of 3u-acyloxy-l1,20-dioxo-16a-methyl- 5i3-pregnane isadvantageously effected with an alkali metal borohydride in an anhydrouslower alkanol such as sodium borohydride in absolute ethanol. Thecyclization of 3 a-acyloxy-l l-oxo-20hydr0xy-16a-rnethyl-5ppregnane maybe efiected at elevated temperatures in the presence of white light anda lead tetraacetate in an inert organic solvent such as benzene. Theoxidation of 30a acyloxy 11 oxo 18,20 oxido 16a. methyl- SB-pregnane maybe effected at room temperatures with an oxidizing agent such assulfochromic acid and the subsequent saponification of the 3a-acyloxygroup may be performed at room temperature under alkaline conditionswith an alkali metal or alkaline metal hydroxide as preferred alkalineagents. Sodium hydroxide is a preferred agent because of easyavailability. The reduction of3a,20-dihyd1'OXY-11,18-diOXO-18,Z0-OXidO-16amethyl-SB-pregnane ispreferably performed with an alkali metal borohydride such as sodiumborohydride and is followed by acidification with an inorganic acid suchas hydrochloric acid or sulfuric acid.

The 18,11 lactone of30:,115,20fi-trihydroxy-16a-methyl-Sfl-pregnane-lSfi-Dic acid is avaluable intermediate for the production of l6oc-methyl-aldosteronewhich possesses enhanced aldosterone activity. The reaction scheme forthe preparation of 16oc-II16thYl aldosterone is illustrated in Table II.

TABLE II O -CHr-OH;

CH O AC OHZOH The acyl radical of the compounds of the invention is theacyl radical of an organic carboxylic acid of 1 to 18 carbon atoms.Suitable carboxylic acids are the alkanoic and alkenoic acids such asacetic acid, trimethyl acetic acid, propionic acid, 4,4-dimethylpentanoic acid, undecylenic acid; cycloalkanoic acids such asB-cyclopentyl propionic acid; arylalkanoic acids such as phenylpropionic acid; cycloalkyl acids such as hexahydrobenzoic acid andhexahydro-terephthalic acid; and arylcarboxylic acid such as benzoicacid and 3,5-dinitrobenzoic acid.

The isomers of the 3a-acyloxy-l1-oxo-l8,20-oxido-l6amethyl-Sfi-pregnaneand the 3m-acyloxy-11-oxo-20-hydroxy-16ot-methyl-5B-pregnane may beisolated if desired, but the process may be operated with mixtures ofthe isomers without adverse effects.

The starting compounds, the 3ot-acyloxy-11,20-dioxo-16a-methyl-5fi-pregnanes, are obtained by the process described bySarett et al. (J.A.C.S., vol. 80, 1958, page 3160).

In the following examples there are described several preferredembodiments to illustrate the invention. However, it should beunderstood that the invention is not intended to be limited to thespecific embodiments.

EXAMPLE.PREPARATION OF THE 18-11 LAC- TONE OF3a,115,20,8-TRIHYDROXY-l6a-METH- YL-SB-PREGNANE- 1 85-010 ACID StageA.-Preparalion of 3a-acet0xy-1I-oxo-ZO-hydroxy- Ida-methyl-Sfi-pregnane(III 30: acetoxy-16u-methyl-11,20-dioxo-5B-pregnane (II) was dissolvedin 40 volumes of absolute ethanol by heating to around 40 C. Thesolution was cooled to 20 C., 0.2 part of sodium borohydride was addedand the mixture was agitated for one hour. Then 0.5 volume of aceticacid was added.

The reaction mixture was then poured into 80 volumes of Water. Thecrystalline precipitate obtained was filtered, washed with water untilthe Wash water was neutral and finally dried at 80 C.

The precipitate was a mixture of the 20mand 205- hydroxy isomers of3a-acetoxy-11-oxo-20-hydroxy'16amethyl-SB-pregnane (III).

The raw reduction product was taken up with methylene chloride, thesolution was concentrated to a small volume and was added to ethylacetate. The removal of the solvent was continued until crystallizationoccurred at the elevated temperature. The two isomers were separatedthrough selective crystallization from methylene chloride, then fromethyl acetate. This operation was repeated several times. The yield ofthe ZOE-isomer of 3a acetoxy 11 oxo 20 hydroxy 16o; methyl 519- pregnanewas of the order of 60%; M.P.=208 C., specific rotation [a] =+58i1(c.=1% in chloroform).

The product was soluble in chloroform, ethanol, benzene, acetone,slightly soluble in ether, insoluble in water and dilute aqueous acids.Dilute aqueous alkalis caused saponification in the 3-position.

This compound is not described in the literature.

The ZOa-hYdIOXY isomer of 3wacetoxy-11-oxo-20-hydroxy-l6a-methyl-58-pregnane was recovered from the dry residue of the mother liquors ofthe purification of the ZOfi-isomer. This dry residue was taken up inbenzene, subjected to chromatography on alumina, washed with acid andeluted with benzene. The chromatography was repeated again and the20a-isomer was recrystallized from ether. A third chromatography overalumina with a mixture of cyclohexane and benzene in equal parts wasmade and elution was efiected with the same mixture.

Crystallization was made at elevated temperatures by solution inmethylene chloride with addition of cyclohexane and distillation of thesolvents. About 6% of the ZOu-isomer of3a-acetoxy-11-oxo-20-hydroxy-16u-methyl- SB- regnane was obtained,having a melting point of 165 C., and a specific rotation [a] =-|67i1(c.=1% in chloroform).

The product was soluble in chloroform, ethanol, acetone, benzene,slightly soluble in ether, insoluble in water and dilute aqueous acids.Dilute aqueous alkalis saponified the 3-position.

This compound is not described in the literature.

Analysis.-C H O molecular weight==390.54. Cal- ;ugted: C, 73.80%; H,9.81%. Found: C, 74.0%; H,

Stage B.Preparation of 3 a-acet0xy-1 1 -ox0-1 8,20-0x1'd0-16a-methyl-5fi-pregnane (IV); isomers 18,200: and ZOB-OXidO (a)Preparation of the 18,20B-0xido isomer.60 gms. of 3a acetoxy-l1-oxo-203-hydroxy-l6ot-methyl-5B-pregnane were dissolved in 1.6 liters ofbenzene and about 200 cc. of benzene were distilled oil in order toremove all traces of moisture. gms. of lead tetraacetate were introducedquite rapidly. The reaction mixture was maintained at reflux underagitation and irradiation with white light for six hours (irradiationwith a 100 watt lamp at 3 cm. distance).

The mixture was cooled. The excess of lead tetraacetate was decomposedby the addition of 20 cc. of ethylene glycol.

Next, the reaction mixture was washed successively with water, then witha saturated sodium bicarbonate solution and again with water. Thebenzene layer containing 341- acetoxy 11oxo-l8,20fi-oxido-16u-methyl-5,3 pregnane was dried over magnesiumsulfate and evaporated to dryness.

The raw product was taken up in petroleum ether and allowed tocrystallize overnight. The crystals were washed by trituration withcyclohexane, then with petroleum ether.

Purification was made by chromatography over alumina (acid-washed) inbenzene and recrystallization from cyclohexane. After recovery of themother liquor by chromatography on alumina, 29.573 gms. of3a-acetoxy-11- oxo-18,20fl-oxido-l6tx-methyl-5 fl-prcgnane wereobtained. This was a yield of 50% of a product having a melting point ofC. and a specific rotation ]D =+65i1 (c.=1% in chloroform).

The product was soluble in ethanol, ether, acetone, benzene, chloroform,slightly soluble in cyclohexane, petroleum ether, insoluble in water anddilute aqueous acids. Dilute aqueous alkalis caused saponification inthe 3-position.

The product is not described in the literature.

Analysis.C H O molecular weight=388.528. Calculated: C, 74.19%; H,9.34%; O, 16.47%. Found: C, 74.0%; H, 9.2%; O, 17.0%.

(b) Preparation of the 18,20a-0xid0 is0mer.-1.5 gms.

of 30a acetoxy-ll-oxo-20a-hydroxy-l6a-methyl-5B-pregnane were dissolvedin 75 cc. of benzene and then 25 cc. of solvent were distilled oil inorder to eliminate all trace of moisture. 3 gms. of lead tetraacetatewere introduced quite rapidly under agitation and under luminousactivation (as indicated above). The reaction mixture was maintained forabout two hours at reflux temperature, then cooled in the absence ofluminous irradiation. The excess lead tetraacetate was destroyed byaddition of 0.5 cc. of ethylene glycol. I Next, the benzene solution ofthe reaction mixture was washed successively with water, with saturatedsodium bicarbonate solution and again with water. The benzene layercontained 30: acetoxy 11 oxo-18,20a-oxido-l6umethyl-SB-pregnane and wasdried over magnesium sulfate and evaporated to dryness.

The raw product was taken up in ether. The solids were separated andrecrystallized from mixed cyclohexane and methanol. 0.502 gm. of thecompound were obtained Stage C .----Preparation of 3a,20-dihydroxy-11,18-dix0- 18,20-0xid0-1 6 a-methyI-S p-pregnane (V) 16 gms. of3a-acetoxy-ll-oxo-l8,20fl-oxido-16a-methyl- B-pregnane were dissolved in160 cc. of acetic acid at 20 C. 56 cc. of a snlfochromic acid solutiontitrating 24.45 gms. of chromic acid per 100 cc. were then introducedunder agitation at 20 C. into the solution. The reaction mixture wasallowed to stand overnight at room temperature, then water was added. Agummy precipitate was formed. The suspension was extracted withmethylene chloride several times, the organic extracts were united,washed with water, dried over magnesium sulfate and evaporated todryness.

The residue was taken up with ether; the acid fraction was extracted bycountercurrent extraction with a 1N solution of sodium hydroxide andfinally the exhausted ethereal layer was extracted with the same sodiumhydroxide solution.

The alkaline phases were united and washed with ether and acidified byhydrochloric acid until the pH was restored to 1. This caused a gummyprecipitate.

The precipitate was extracted by methylene chloride. The extracts werewashed with water, dried over magnesium sulfate and the solvent wasevaporated. The crystalline paste obtained was washed by triturationwith isopropyl ether and dried. After recrystallization from warmacetone, 4.686 gms. of 3a,20-dihydroxy-11,18-dioxo-18,20-oxido-l6u-methyl 5/3-pregnane were obtained, being a yield ofabout 30%. The product had a melting point of 210 C. and a specificrotation The product was soluble in ethanol, acetone and dilute aqueousalkalis, very slightly soluble in benzene and chloroform and insolublein water and dilute aqueous acids.

Formula: C H O molecular Weight=376.48. The product is not described inthe literature.

3 u,20-dihydroxy-1 1, l S-dioxol 8,20-oxido-l 6OL-1'HEthYl-5 5- pregnanewas also obtained starting from the 20a-isomer of3a-acetoxy-1l-oxo-l8,20u-oxido-l6a-methyl-5/8 pregnane by dissolving0.502 gm. of said 20a-isomer in 7.5 cc. of acetic acid and treating inthe same fashion as in the case of the fi-isomer with 1.75 cc. of thesame sulfochromic acid solution. After the usual recovery steps andrecrystallization from ether containing 10% acetone, 0.152 gm. of3oz,20-dihydroxy-11,18-dioxo-18,20-oxido- 16ot-methyl-5B-pregnane havinga melting point of 210 C. identical with the preceding were obtained.

Stage D.Preparati0n of the 18-11 lactone of 3a,11B,Z0/3- trihydroxy-I6a-methyl-5fl-pregnane-1 8 3-oic acid (I) 2 =grns. of the compoundproduced in stage C were dissolved in 100 cc. of a 1 N sodium hydroxidesolution. Then 1 gm. of sodium borohydride was added and the reactionmixture was placed on a water bath for about three hours. By theaddition of hydrochloric acid, the reaction mixture was adjusted to a pHof 1 and heated to a temperature on the order of 80 C. for five minutes.The precipitate obtained was vacuum filtered, washed with water untilthe wash water was neutral, taken up by acetone and the solventeliminated. The

8 crystals obtained were washed with ether and dried at C. 1.211 gms. ofthe 18-11 lactone of 3a,11fi,20fitrihydroxy-lGa-methyl-Sfi-pregnane-I8fi-oic acid were obtained, being ayield of 64% This product had a melting point of 213 C. and a specificrotation [a] =i+45 :1 (c.=1% in acetone).

The product was soluble in acetone, slightly soluble in dilute aqueousacids, insoluble in water, ether, benzene and chloroform.

Analysis.C I-I O molecular weight=362.49. Ca1- culated: C, 72.89%; H,9.45%. Found: C, 72.9%; H, 9.4%.

This product is not described in the literature.

Stage E.Preparation of the 18-11 lactone 0f 30:,11520/8- trihydroxy-I6u-methyl-5B-pregnane-1 813-0ic acid 311,205- diacetate (I, R=COCH To0.5 gm. of the compound produced in stage D was added 2 cc. of pyridineand 1 cc. of acetic anhydride. The reaction mixture was allowed to standfor twentyfour hours. Then, water was added under refrigeration. An oilylayer was formed which crystallized after some time. The crystals werewashed with water and dried at 80 C.

The product was purified by recrystallization in methylene chloride andisopropyl ether. 0.382 gm. of 18-11 lactone of3a,11,3,20f3-trihydroxy-16u-methyl-5e-pregnane- 18,8-oic acid3a,20p-diacetate were obtained having a melting point of 15-1-153 C. anda specific rotation [u] +47i1 (c. =1% in chloroform).

The product was soluble in ethanol, ether, acetone, benzene, chloroform,isopropyl ether, insoluble in water and dilute aqueous acids. Diluteaqueous alkalis caused saponification of the esterified groups.

Analysis.-C H O molecular weight=444.56. Calculated: C, 69.93%; H,8.58%. Found: C, 70.0%; H, 8.4%.

This product is not described in the literature.

Various modifications of the process of the present invention may bemade without departing from the spirit or scope thereof, and it is to beunderstood that the invention be limited only as defined in the appendedclaims.

We claim:

1. A compound having the formula 9. The process of preparing a compoundhaving the formula wherein R is a member selected from the groupconsisting hydrogen and an acyl radical of an organic carboxylic acidhaving 1 to 18 carbon atoms which comprises reducing3u-acyloxy-11,20-dioxo-16u-methyl 55 pregnane to form 30: acyloxy1l-oxo-ZO-hydroxy-l6a-methyl-5B- pregnane, cyclizing the latter to form3a-acyloxy-11-oxo- 18,20-oxido-l6a-methyl-5fi-pregnane, oxidizing andsaponifying the 18,20oxido product to form 3a,20-dihydroxy- 11,18-dioXo-18,20-oxido-16a-methy1-5B-pregnane, reducing the latter18,20-xido product to form the 18-11 lactone of3a,11,8,20B-trihydroxy-l6a-methyl 5B pregnanc- 18/3-0ic acid andrecovering the desired product.

10. The process of claim 9 wherein the reduction of 30a acyloxy 11,20dioxo-l6a-methyl-5fi-pregnane is effected in the presence of sodiumborohydride in absolute ethanol.

11. The process of claim 9 wherein the cyclization of 3u-acyloxy 11oxo-ZO-hydroxy-l6a-methyl-5/8-pregnane is effected with leadtetraacetate in benzene at elevated temperatures with activation bylight.

12. The process of claim 9 wherein the oxidation of3u-acyloxy-1I-oxo-18,20-oxido-16a-methyl 5o pregnane is carried outwithsulfochromic acid and at room tempera- 10 tures and is then saponifiedwith sodium hydroxide at room temperatures.

13. The process of claim 9 wherein the reduction of 3a,20 dihydroxy11,-18-dioxo-18,20-oxido-16u methyl- Sfl-pregnane is effected in thepresence of sodium borohydride.

14. The process of preparing a compound having the formula SRO-- whereinR is a member selected from the group consisting of hydrogen and an acylradical of an organic carboxylic acid having 1 to 18 carbon atoms whichcomprises reducing 3u-acyloxy-11,20-dioxo-IGa-methyI-Sfl-pregnane withsodium borohydride in absolute ethanol to formacyloxy-l1-oxo-20-hydroxy-16a-methy1-5 8 pregnane, cyclizing the latterwith lead tetraacetate in benzene at elevated temperatures and activatedwith light to form 30:- acyloxy 11 oxo 18,20-oxido-1Ga-methyl-SB-regnane, oxidizing the 18,20-oxido product with sulfochromic acid atroom temperature and saponifying in the presence of sodium hydroxide atroom temperatures to form 30:,20- dihydroxy 11,18 dioxo18,20-oxido-16amethyl 5B- pregnane, reducing the latter 18,20-0Xido product with sodiumborohydride and recovering the desired product.

No references cited.

1. A COMPOUND HAVING THE FORMULA